OBJECTIVE: To find out the circuit pressure and flow at the trigger point by observing the characteristics of the inspiratory trigger waveform of the ventilator, confirm the intra-alveolar pressure as the index to reflect the effort of the trigger according to the working principle of the ventilator combined with the laws of respiratory mechanics, establish the related mathematical formula, and analyze its influencing factors and logical relationship. METHODS: A test-lung was connected to the circuit in a PB840 ventilator and a SV600 ventilator set in pressure-support mode. The positive end-expiratory pressure (PEEP) was set at 5 cmH₂O (1 cmH₂O ≈ 0.098 kPa), and the wall of test-lung was pulled outwards till an inspiratory was effectively triggered separately in slow, medium, fast power, and separately in flow-trigger mode (sensitivity V_Trig 3 L/min, 5 L/min) and pressure-trigger mode (sensitivity P_Trig 2 cmH₂O, 4 cmH₂O). By adjusting the scale of the curve in the ventilator display, the loop pressure and flow corresponding to the trigger point under different triggering conditions were observed. Taking intraalveolar pressure (Pa) as the research object, the Pa (called P_a-T) needed to reach the effective trigger time (T_T) was analyzed in the method of respiratory mechanics, and the amplitude of pressure change (ΔP) and the time span (ΔT) of Pa during triggering were also analyzed. RESULTS: (1) Corresponding relationship between pressure and flow rate at TT time: in flow-trigger mode, in slow, medium and fast trigger, the inhalation flow rate was V_Trig, and the circuit pressure was separately PEEP, PEEP-Pn, and PEEP-Pn' (Pn, Pn', being the decline range, and Pn' > Pn). In pressure-trigger mode, the inhalation flow rate was 1 L/min (PB840 ventilator) or 2 L/min (SV600 ventilator), and the circuit pressure was PEEP-P_Trig. (2) Calculation of P_a-T: in flow-trigger mode, in slow trigger: P_a-T = PEEP-V_TrigR (R represented airway resistance). In medium trigger: P_a-T = PEEP-Pn-V_TrigR. In fast trigger: P_a-T = PEEP-Pn'-V_TrigR. In pressure-trigger mode: P_a-T = PEEP-P_Trig-1R. (3) Calculation of ΔP: in flow trigger mode, in flow trigger: without intrinsic PEEP (PEEPi), ΔP = V_TrigR; with PEEPi, ΔP = PEEPi-PEEP+V_TrigR. In medium trigger: without PEEPi, ΔP = Pn+V_TrigR; with PEEPi, ΔP = PEEPi-PEEP+Pn+V_TrigR. In fast trigger: without PEEPi, ΔP = Pn'+V_TrigR; with PEEPi, ΔP = PEEPi-PEEP+Pn'+V_TrigR. In pressure-trigger mode, without PEEPi, ΔP = P_Trig+1R; with PEEPi, ΔP = PEEPi-PEEP+P_Trig+1R. (4) Pressure time change rate of Pa (F_P): F_P = ΔP/ΔT. In the same ΔP, the shorter the ΔT, the greater the triggering ability. Similarly, in the same ΔT, the bigger the ΔP, the greater the triggering ability. The FP could better reflect the patient's triggering ability. CONCLUSIONS The patient's inspiratory effort is reflected by three indicators: the minimum intrapulmonary pressure required for triggering, the pressure span of intrapulmonary pressure, and the pressure time change rate of intrapulmonary pressure, and formula is established, which can intuitively present the logical relationship between inspiratory trigger related factors and facilitate clinical analysis.
Humans ; Respiration, Artificial/methods* ; Positive-Pressure Respiration ; Lung ; Ventilators, Mechanical ; Respiratory Mechanics

Objective:To understand the status of two -week prevalence and the influencing factors in rural preschool leftover children of Shandong , so as to provide evidence for putting forward effective health intervention means .Methods:Using the method of stratified -cluster-random sampling and elect 646 cases of preschool lefto-ver children from 2 counties of Shandong .We surveyed with self -made questionnaire .Results:The two-week prevalence of the rural preschool leftover children is high;the influencing factors of the two -week prevalence with the rural preschool leftover children including whether children are only -child, the type of children guardianship , whether children piddle and whether left -behind children can avoid dangerous .Conclusion: The two -week prevalence present situation of rural preschool left -behind children is low , and its problems of health and ethics are clear.Therefore, effective measures should be carried out to improve the health level of rural leftover children .

OBJECTIVETo investigate the triaging pathways of patients after coronary computed tomography angiography (CCTA).

METHODSThe patients undergoing CCTA were enrolled consecutively during the period from March 3, 2008 to June 23, 2009. The rate of coronary angiography (CAG) examinations after CCTA was calculated. The rates of normal CAG, medication, percutaneous coronary intervention (PCI), and coronary artery bypass graft (CABG) were compared between CCTA and direct CAG cohorts.

RESULTSA total of 8030 cases receiving CCTA and 3260 receiving direct CAG were included in the study. The CCTA patients had significantly fewer risk factors than those having direct CAG. Of the 8030 patients undergoing CCTA, 953 (12.03%) received further CAG and 6977 (87.97%) did not. Of the patients who received CAG after CCTA, 35 (3.7%) had normal CAG findings, 604 (63.4%) underwent PCI, 108 (11.3%) received conservative treatment with medications, and 206 (21.6%) underwent CABG. In the 3260 patients directly undergoing CAG, 706 (52.3%) underwent subsequent PCI, 142(4.4%) underwent CABG, 815(25.1%) received medications, and 579 (17.9%) had normal CAG findings. Comparison between the cases receiving direct CAG and CAG after CCTA showed that CCTA resulted in a significant increase in the revascularization rate (P<0.0001).

CONCLUSIONCCTA can help prevent unnecessary CAG and allows more accurate patient triage.

Coronary Angiography ; methods ; Coronary Artery Disease ; diagnostic imaging ; therapy ; Female ; Humans ; Male ; Middle Aged ; Percutaneous Coronary Intervention ; Retrospective Studies ; Risk Factors ; Tomography, X-Ray Computed

Objective To investigate the triaging pathways of patients after coronary computed tomography angiography (CCTA). Methods The patients undergoing CCTA were enrolled consecutively during the period from March 3, 2008 to June 23, 2009. The rate of coronary angiography (CAG) examinations after CCTA was calculated. The rates of normal CAG, medication, percutaneous coronary intervention (PCI), and coronary artery bypass graft (CABG) were compared between CCTA and direct CAG cohorts. Results A total of 8030 cases receiving CCTA and 3260 receiving direct CAG were included in the study. The CCTA patients had significantly fewer risk factors than those having direct CAG. Of the 8030 patients undergoing CCTA, 953 (12.03%) received further CAG and 6977 (87.97%) did not. Of the patients who received CAG after CCTA, 35 (3.7%) had normal CAG findings, 604 (63.4%) underwent PCI, 108 (11.3%) received conservative treatment with medications, and 206 (21.6%) underwent CABG. In the 3260 patients directly undergoing CAG, 706 (52.3%) underwent subsequent PCI, 142(4.4%) underwent CABG, 815(25.1%) received medications, and 579 (17.9%) had normal CAG findings. Comparison between the cases receiving direct CAG and CAG after CCTA showed that CCTA resulted in a significant increase in the revascularization rate (P<0.0001). Conclusion CCTA can help prevent unnecessary CAG and allows more accurate patient triage.

Objective To investigate the triaging pathways of patients after coronary computed tomography angiography (CCTA). Methods The patients undergoing CCTA were enrolled consecutively during the period from March 3, 2008 to June 23, 2009. The rate of coronary angiography (CAG) examinations after CCTA was calculated. The rates of normal CAG, medication, percutaneous coronary intervention (PCI), and coronary artery bypass graft (CABG) were compared between CCTA and direct CAG cohorts. Results A total of 8030 cases receiving CCTA and 3260 receiving direct CAG were included in the study. The CCTA patients had significantly fewer risk factors than those having direct CAG. Of the 8030 patients undergoing CCTA, 953 (12.03%) received further CAG and 6977 (87.97%) did not. Of the patients who received CAG after CCTA, 35 (3.7%) had normal CAG findings, 604 (63.4%) underwent PCI, 108 (11.3%) received conservative treatment with medications, and 206 (21.6%) underwent CABG. In the 3260 patients directly undergoing CAG, 706 (52.3%) underwent subsequent PCI, 142(4.4%) underwent CABG, 815(25.1%) received medications, and 579 (17.9%) had normal CAG findings. Comparison between the cases receiving direct CAG and CAG after CCTA showed that CCTA resulted in a significant increase in the revascularization rate (P<0.0001). Conclusion CCTA can help prevent unnecessary CAG and allows more accurate patient triage.

Objective To assess the relationship between coronary plaques and risk factor of coronary heart disease in a asymptomatic population.Methods A total of 604 in-patients who received coronary computerized tomography angiography (CCTA) during January 1 th,2010 and April 1 th,2011 were enrolled in this study and assigned to the non-lesion group (0),mild lesion group (0 ＜ score ≤ 5) andmoderate-severe lesion group (＞ 5) according to the third quartile of CCTA score.Clinical data including physical examination,laboratory test,ultrasound sonogram and discharge diagnoses were collected and compared between the groups.Multivariable linear regression and bivariate logistic regression were performed to find out the main risk factors of coronary heart disease.ROC curve was drawn to estimate the diagnostic value of coronary lesions.Results There were 240 individuals in the non-lesion group,271 in the mild lesion group,93 in the moderate-severe lesion group.Multivariable linear regression indicated Y =-6.56 +3.22 × mean carotid intima-media thickness (cIMT) + 1.106 × male + 0.597 × low-density lipoprotein cholesterol (LDL-C) + 0.116 × age-1.596 × high-density lipoprotein cholesterol (HDL-C).Bivariate logistic regression and ROC curve showed that mean cIMT was the main risk factor of coronary heart disease (odds ratio (OR) =7.19,ROC =0.730,P=0.00,95％ confidence interval (CI):0.68 to 0.78).Furthermore,major coronary lesions were located in the LAD (20.8％) and was soft plaque (42.5％).Conclusion In this investigation,60.2％ of the asymptomatic patients showed plaques in CCTA.Age,cIMT,LDL-C and HDL-C may be predictive to moderate to severe coronary artery lesions.

Objective To discuss the influence of coronary computed tomography angiography(CCTA)on correctness of assessing revascularization in patients with coronary artery disease. Methods A retrospective study method was conducted,605 cases underwent CCTA before coronary angiography(CAG)from 2008 to 2009 in Chinese PLA General Hospital were selected as CCTA before CAG group,and meanwhile 616 cases examined by CAG directly were selected as direct CAG group. Patients with multiple procedures of CAG were excluded. The proportions of various treatment strategies were compared,including per-cutaneous coronary intervention(PCI),coronary artery bypass grafting(CABG),medical therapy(MT),normal rate of CAG and the correctness of assessing revascularization between the two groups. Results The comparison between the baseline of the two groups showed that in the CCTA before CAG group,there were more severe lesions than those in the direct CAG group,such as Syntax score(11.31±8.90 vs. 10.23±9.73,P<0.05). Compared with direct CAG group,the triage of PCI and CABG in the CCTA before CAG group was significantly increased〔PCI:65.3%(395/605)vs. 57.1%(352/616),CABG:16.5%(100/605)vs. 3.4%(21/616)〕,while the percentages of medical treatment and normal CAG were obviously reduced〔medical treatment:11.7%(71/605)vs. 19.3%(119/616),normal rate of CAG:6.4%(39/605)vs. 20.1%(124/616),all P<0.01〕. With the guidance of CCTA,the correctness of assessing revascularization was increased〔81.8%(495/605)vs. 60.6%(373/616),P<0.01〕. Conclusion Compared with the direct induction by CAG,the CCTA examination carried out before CAG is capable of increasing the rate of correctness in the determination of revascularization in coronary heart diseases.

OBJECTIVETo investigate the correlation between the findings by coronary computed tomography angiography (CCTA) and the risk factors for major adverse cardiac events (MACE).

METHODSThis cohort study involved 706 out-patients who received examination with CCTA between June, 2008 and April, 2011. The severity of coronary artery disease (CAD) was graded to normal, mild, moderate, severe, and revascularization. Pearson correlation analysis and ANOVA were used to evaluate the relationship between the risk factors for CAD and coronary plaques identified by CCTA, and the predictive accuracy was determined by the receiver-operating characteristic (ROC) curve.

RESULTSOf the 706 patients, 58.63% were found to have abnormal CCTA findings. A older age, hypertension, hyperlipidemia, diabetes mellitus, cerebral infarction, CAD, and myocardial infarction were associated with an significantly increased incidence of coronary plaques (P<0.01). The Framingham score, LDL, HCY, IMT, HDL and TC were also significantly correlated with the severity of the coronary plaques (P<0.05). The ROC curves showed that Framingham risk score (0.845), Cr (0.766), HCY (0.697), IMT (0.693) and HDL (0.316) had greater predictive value for the occurrence of coronary plaques (P<0.001).

CONCLUSIONThe Framingham risk score, Cr, HCY, IMT and HDL are validated by CCTA as the major coronary risk factors and can be used for screening of CAD.

Aged ; Coronary Angiography ; methods ; Coronary Artery Disease ; diagnostic imaging ; Cross-Sectional Studies ; Female ; Humans ; Male ; Middle Aged ; Risk Factors ; Tomography, Spiral Computed ; Tomography, X-Ray Computed ; methods

OBJECTIVETo assess the value of contrast-enhanced ultrasonography (CEUS) and fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸F-FDG PET/CT) in evaluating the stability of carotid atherosclerosis.

METHODSSeventeen patients with 21 carotid artery plaques received examinations with CEUS. According to the nature of the plaques, the patients were divided into soft and mixed plaque group and hard and calcified plaque group. The maximal enhancement intensity of the plaques (I(MAX)) and maximal plaque density (D(MAX)) were measured to quantify the neovasculature. The patients also underwent concurrent ¹⁸F-FDG PET/CT, and ¹⁸F-FDG uptake was quantified by the mean standard uptake values (SUV(mean)), an index reflecting the inflammatory activity in the plaque. The findings in CEUS and PET/CT were comparatively analyzed for these cases.

RESULTSThe D(MAX) of the plaque in soft and mixed plaque group was significantly greater than that in hard and calcified plaque group (4.26±3.65 vs 1.41±1.47, P<0.05); the I(MAX) was also greater in the former group, but this difference was not statistically significant (26.83±19.61 vs 24.73±29.85, P=0.869). The soft and mixed plaques tended to have higher SUVmean than the hard and calcified plaques (1.70±0.45 vs 1.47±0.12, P=0.099). The values of I(MAX) and D(MAX) were not found to correlate to SUV(mean) in these patients.

CONCLUSIONCEUS can sensitively show the status of neovascularization within the carotid atherosclerosis plaques, and PET/CT reflects the inflammatory activity in the plaques. The combination of these two imaging modalities allows the evaluation of plaque stability in terms of neoangiogenesis and inflammatory activity.

Aged ; Aged, 80 and over ; Carotid Stenosis ; diagnostic imaging ; Female ; Fluorodeoxyglucose F18 ; Humans ; Male ; Middle Aged ; Positron-Emission Tomography ; Tomography, X-Ray Computed